
What it is
Diazolidinyl Urea is a white powder.
What it does
Diazolidinyl Urea is a preservative that prevents bacterial growth. It works by releasing small amounts of formaldehyde, a toxic and carcinogenic substance used to embalm dead bodies.
Side effects
The Cosmetic Ingredient Review (CIR) Expert Panel considers Diazolidinyl Urea safe to be used in cosmetics up to a maximum concentration of 0.5%. In Europe, when the concentration of formaldehyde in the finished product exceeds 0.05%, the labels has to state “contains formaldehyde”.
Diazolidinyl Urea can cause irritations and allergies.
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Wow, this sounds dangerous and terrifying. I’ll keep an eye if it’s in the products I use now.
Hi Jasmine, I didn’t mean to cause a scare. Formaldehyde is really nasty stuff and although the FDA says it isn’t dangerous in very small quantities I stay away from it. I don’t think it’s gonna kill since the concentrations are low, but still who would want toxic stuff in their bodies in the first place? I’d rather have no formaldehyde at all instead of small amounts in the first place, esp when there are other preservatives who work just as well but don’t release any toxic stuff.
I like your ‘know your ingredients’ series of posts. Very informative!

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Thank you Vonvon, I’m glad you’re enjoying these posts!
Is diazolidinyl urea derived from animal urine or is it entirely synthetic?
Hi Barbara, diazolidinyl urea can be derived both from animal or synthetic sources. However in cosmetics products diazolidinyl urea is made by the reaction of allantoin (a substance derived from the extracts of the comfrey plant) and formaldehyde.
Thanks for fast reply. I work in retail and a gentleman customer refused to buy a hand softener because of this ingredient thinking it a derivative of urine. He piqued my interest. the websites I checked were not clear on the source either.
You’re welcome Barbara. There is a lot of confusion on this topic because some ingredients, like Urea, are components of urine. But in cosmetics, synthetic versions are used. You can tell your clients not too worry, they won’t be putting urine on their faces.
thanks barbara for bringing up this matter as i’m having the same confusion too
Feyda Fauzan, I’m glad this helped clearing up any doubts. Thanks to Barbara too .